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Inspection Procedure

NOTE: When the seat belt control ECU is replaced with a new one, Initialization must be performed (See INITIALIZATION  ).
  1. INSPECT FUSE (PSB) 
    1. Remove the PSB fuse from the main body ECU LH (cowl side junction block LH).
    2. Measure the resistance according to the value (s) in the table below.

      Standard Resistance 

      STANDARD RESISTANCE SPECIFICATION

      Tester Connection Condition Specified Condition
      PSB fuse Always Below 1 Ω

    NG: REPAIR OR REPLACE FUSE 

    OK: Go to next Step 

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) 
    1. Disconnect the cable from the negative (-) battery terminal.
      CAUTION: Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.
      NOTE: When disconnecting the cable, some systems need to be initialized after the cable is reconnected (See INITIALIZATION ).
    2. Disconnect the Q38 connector of the seat belt control ECU.
    3. Connect the cable to the negative (-) battery terminal
    4. Measure the voltage according to the value (s) in the table below.

      Standard Voltage 

      STANDARD VOLTAGE SPECIFICATION

      Tester Connection Condition Specified Condition
      Q38-3 (IG1) - Body ground Engine switch off Below 1 V
      Engine switch on (IG) 11 to 14 V
      Q38-9 (+B) - Body ground Always 11 to 14 V
      5. Fig 1: Identifying Q38 Seat Belt Control ECU Connector Terminal
      G05754829Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next Step 

  3. CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT) 
    1. Disconnect the cable from the negative (-) battery terminal.
      CAUTION: Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.
      NOTE: When disconnecting the cable, some systems need to be initialized after the cable is reconnected (See INITIALIZATION ).
    2. Measure the resistance according to the value (s) in the table below.

      Standard Resistance 

      STANDARD RESISTANCE SPECIFICATION

      Tester Connection Condition Specified Condition
      Q38-18 (PGND) - Body ground Always Below 1 Ω
      3. Fig 2: Identifying Q38 Seat Belt Control ECU Connector Terminal
      G05754830Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE SEAT BELT CONTROL ECU  (See SEAT BELT CONTROL ECU  )

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